System, device and method for transforaminal lumbar interbody fusion

ABSTRACT

A transforaminal lumbar interbody (TLIF) implant, installation tool, and method of use includes a TLIF implant having a cavity, a first slot extending along an outside surface of a first lateral wall, and a second slot extending along an outside surface of a second lateral wall, the slots configured to receive an installation tool for holding the TLIF implant. The cavity houses a first impacted blade and a second impacted blade. When driven by the installation tool, guides in the walls of the cavity direct the impacted blades along the inside of the cavity such that ends of the blades extend from the cavity and beyond the implant body. The end of the first impacted blade extends from an upper side of the cavity and beyond the implant body, while the end of the second impacted blade extends from a lower side of the cavity and beyond the implant body.

FIELD OF THE INVENTION

The present invention relates to methods and devices for orthopedicsurgery of the spine and, particularly, to methods and devices fortransforaminal lumbar interbody fusion (TLIF).

BACKGROUND OF THE INVENTION

Many people contend with spine issues as a result of age, disease, andtrauma, as well as congenital and acquired complications and conditions.While some of these issues can be alleviated without surgery, otherissues necessitate surgery. Spinal fusion may be recommended forconditions such as spondylolistheses, degenerative disc disease, orrecurrent disc herniation, and is designed to create solid bone betweenadjacent vertebrae, thereby eliminating any movement between the bones.A spinal fusion uses an implant or device known as an interbody cage orspacer along with bone graft and/or bone graft substitute that isinserted into the disc space between adjacent vertebrae from one side ofthe spine. Typically, additional surgical hardware (implants) such aspedicle screws and rods or plates are attached to the back of thevertebrae. As the bone graft heals, it fuses the adjacent vertebrae toform one long vertebra.

A fusion of the lumbar region of the spine (a lumbar fusion) may beaccomplished using several techniques. Once such technique is known as atransforaminal lumbar interbody fusion or TLIF. TLIF spine surgery isperformed through the posterior aspect of the spine and providesstabilization of the anterior portion by an interbody cage and bonegraft while the posterior portion is locked in place with pediclescrews, rods and bone graft. A TLIF procedure is advantageous over aposterior lumbar interbody fusion (PLIF) and other lumbar fusionprocedures for several reasons. In a TLIF procedure, bone fusion isenhanced because bone graft is not only placed along the “gutters” ofthe spine posteriorly, but also in the disc space. A TLIF procedure alsoallows the surgeon to insert bone graft and an interbody cage into thedisc space laterally from a unilateral approach without forcefullyretracting the nerve roots as much as the PLIF approach, which canreduce injury and scarring around the nerve roots. However, there isroom for improvement over current TLIF implants, instruments, and/orsurgical procedures.

In view of the above, it is an object of the present invention toprovide an improved TLIF implant, an instrument for implanting theimproved TLIF, and/or a surgical procedure for the implantation.

SUMMARY OF THE INVENTION

An implant, instrument, and procedure for a transforaminal lumbarinterbody fusion (TLIF) is provided.

The TLIF implant is characterized by a body having a cavity, anunthreaded hole in an end of the body that is in communication with thecavity, a first slot extending along an outside surface of a firstlateral wall of the body, and a second slot extending along an outsidesurface of a second lateral wall of the body, the first and second slotsconfigured to receive an installation tool for holding the TLIF implant.The cavity houses a first impacted blade and a second impacted blade.When driven by the installation tool, guides formed in the walls of thecavity direct the first and second impacted blades along the inside ofthe cavity such that ends of the first and second blades extend from thecavity and beyond the implant body.

The end of the first impacted blade extends from an upper side of thecavity and beyond the implant body, while the end of the second impactedblade extends from a lower side of the cavity and beyond the implantbody.

The end of the first blade may be barbed. The end of the second blademay likewise be barbed.

Upper (superior) surfaces of the body of the TLIF implant and lower(inferior) surfaces of the body of the TLIF implant may each haveserrations, teeth or otherwise.

The TLIF instrument is characterized by hollow shaft extending from ahandle, the hollow shaft having a distal end with a first prong and asecond prong, the first prong configured for releasable reception in thefirst slot of the TLIF implant body, and the second prong configured forreleasable reception in the second slot of the TLIF implant body. Thehollow shaft receives a movable rod that extends through the handle andhollow shaft, and has a length sufficient for a tip of the rod to extendinto the cavity of the TLIF implant body when the TLIF implant body isheld by the installation tool. The movable rod tip is configured toengage and push the first and second impacted blades of the TLIF implantsuch that ends of the first and second blades extend from the TLIFimplant body.

A yoke may be disposed between the handle and the hollow shaft.

One or more windows (openings) may be formed in the hollow shaft inorder to receive graft for insertion into the TLIF implant. One or moreof the plurality of windows may have an oval shape.

The procedure or method of use/installation includes placing the presentTLIF implant onto the present TLIF implant installation tool. The firstand second prongs at the tip of the shaft of the installation tool arereceived in the first and second outside lateral slots of the TLIFimplant body. The installation tool is thus ready to place the TLIFimplant into the vertebral space previously occupied by a vertebra, thevertebra having been surgically removed prior to implant installation.Once the TLIF implant has been placed at the desired location, themoveable rod with configured tip is inserted into the hollow shaft ofthe installation tool and used to push the impacted blades up and out ofthe implant cavity. The movable blade pushing rod is removed from thehollow shaft of the installation tool and a graft pushing rod isreceived in the installation tool. Graft is inserted through the windowsof the hollow tool shaft. The graft pushing rod is moved to push thegraft through the hollow tool shaft and into the cavity of the installedTLIF implant through the end hole. Once a sufficient amount of graft hasbeen pushed into the implant cavity, the rod and installation tool areremoved.

Further aspects of the present invention will become apparent fromconsideration of the drawings and the following description of a form ofthe invention. A person skilled in the art will realize that other formsof the invention are possible and that the details of the invention canbe modified in a number of respects without departing from the inventiveconcept. The following drawings and description are to be regarded asillustrative in nature and not restrictive.

BRIEF DESCRIPTION OF THE DRAWINGS

The features of the invention will be better understood by reference tothe accompanying drawings which illustrate the present invention,wherein:

FIG. 1 is an isometric rear side view of an exemplary TLIF implantfashioned in accordance with the present principles;

FIG. 2 is a side view of a system for installing a TLIF implant, thesystem showing an instrument for installing the TLIF implant of FIG. 1with the TLIF implant situated on an insertion end of the installationinstrument, the TLIF implant shown in greater detail within anenlargement insert and depicting blades of the TLIF implant in anextended position; and

FIG. 3 is an enlarged partial view of a portion of the TLIF implantinstallation instrument of FIG. 2.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1, there is depicted an exemplary form of atransforaminal lumbar interbody fusion (TLIF) implant, generallydesignated 10, fashioned in accordance with the present principles. TheTLIF implant 10 is made from a biocompatible material such as, but notlimited to, titanium, stainless steel, an alloy of titanium or stainlesssteel, or otherwise. The TLIF implant 10 is characterized by a body 11fashioned generally as a rectangular cuboid or prism having an upper(superior) surface 16, a lower (inferior) surface 17 opposite to theupper surface 16, a first lateral side 14, a second lateral side (notseen) that is opposite to and identical with the first lateral side 14,a first end 12, and a second end 13 opposite to the first end 12, thenomenclature “first” and “second” being arbitrary. The body 11 also hasa cavity 28 that extends from the upper surface 16 to the lower surface17. The cavity 28 is adapted or configured to received bone graft/bonegraft material such as is known in the art.

The first end 12 of the body 11 defines a nose or arch having adownwardly angled or sloped upper (superior) surface 15, an upwardlyangled or sloped lower (inferior) surface (not seen) opposite to thedownwardly angled upper surface 15, a first slanted side 32, and asecond slanted side (not seen) opposite to the first slanted side 32,the nomenclature “first” and “second” being arbitrary. A bore 26 (seeFIG. 2) is provided in the downwardly angled upper surface 15 thepurpose of which is to accept a radio opaque marker to mark the firstend 12 of the implant. The second end 13 of the body 11 is generallyplanar with a large unthreaded bore 23 that extends/providescommunication from the second end 13 into/to the cavity 28. A firstelongated slot 22 runs from a first side of the bore 23 to and along thefirst lateral side 14, while a second elongated slot 30 runs from asecond side of the bore 23 to and along the second lateral side, thenomenclature “first” and “second” being arbitrary. The first elongatedslot 22 is adapted/configured to receive a first prong 107 of theinstallation tool 100 (see FIG. 2), while the second elongated slot 30is adapted/configured to receive a second prong (not seen) of theinstallation tool 100 (see FIG. 2) opposite the first prong 107 asexplained below, the nomenclature “first” and “second” being arbitrary.The first and second elongated slots preferably, but not necessarily,extend a majority of the length of the respective first and secondlateral sides 14, (not seen). An upper (superior) surface 24 and a lower(inferior) surface (not seen) opposite the upper surface 24 of thesecond end 13 are generally planar. A bore 25 (see also FIG. 2) isprovided in the upper surface 24 the purpose of which is to accept aradio opaque marker to mark the second end 13 of the implant.

Extending between the upper surface 24 of the second end 13 and thedownwardly angled upper surface 15 adjacent the first lateral side 14 isa first section of serrations, teeth, or the like (collectively,serrations) 18, while extending between the upper surface 24 of thesecond end 13 and the downwardly angled upper surface 15 adjacent thesecond lateral side (not seen) is a second section of serrations, teeth,or the like (collectively, serrations) 19, the nomenclature “first” and“second” being arbitrary. The serrations 18, 19 provide gripping of theinferior end of a superior vertebra when implanted. In like manner,extending between the lower surface (not seen) of the second end 13 andthe upwardly angled lower surface 27 adjacent the first lateral side 22is a third section of serrations, teeth, or the like (collectively,serrations) 20, while extending between the lower surface (not seen) ofthe second end 13 and the upwardly angled lower surface 27 adjacent thesecond lateral side (not seen) is a fourth section of serrations, teeth,or the like (collectively, serrations) (not seen), the nomenclature“third” and “fourth” being arbitrary. The serrations 20, (not seen)provide gripping of the superior end of an inferior vertebra whenimplanted.

The cavity 38 of the body 11 of the TLIF implant 10 is defined byinterior walls. Particularly, the cavity 38 has a first interior lateralwall (not seen) on the other side of the first lateral side 14, a secondinterior lateral wall 31 on the other side of the second lateral wall(not seen), a first interior end wall 33 on the other side of the firstend 12, and a second interior end wall 34 on the other side of thesecond end 13. As best seen in FIG. 1, the second interior lateral wall31 has an upper ledge 29 that curves upwardly from the second interiorend wall 34 to approximately the first interior end wall 33. While notseen, the second interior lateral wall 31 has a lower ledge that curvesdownwardly from the second interior end wall 34 to approximately thefirst interior end wall 33. In like manner, the first interior lateralwall (not seen) has an upper ledge (not seen) that curves upwardly fromthe second interior end wall 34 go approximately the first interior endwall 33, and a lower ledge (not seen) that curves downwardly from thesecond interior wall 34 to approximately the first interior wall 33. Theupper ledges 29, not seen, define an upper guide or track for an upper(superior) blade 109 (see FIG. 2) while the lower ledges not seen, notseen, define a lower guide or track for a lower (inferior) blade 108(see FIG. 2).

The upper and lower blades 109, 108 are impacted or preferably, but notnecessarily, completely held within the cavity 28 of the body 11. Theupper and lower blades 109, 108, however, are moveable such that distalends of the blades extend out of the cavity 28 and beyond the body 11,such as shown in FIG. 3. When the proximate end (not seen as it iswithin the cavity 28) of the upper blade 109 is pushed by a pushing rodof an installation instrument/tool 100 (see below), the upper blade 109moves along the upper tracks of the inner wall of the cavity such thatthe distal end of the upper blade 109 extends out of the cavity 28 andbeyond the body 11. The distal end of the upper blade 109 may bepointed, barbed or otherwise sharp in order to be received in an upper(superior) spine disc and/or vertebra. When the proximate end (not seenas it is within the cavity 28) of the lower blade 108 is pushed by apushing rod of an installation instrument/tool 100 (see below), thelower blade 108 moves along the lower tracks of the inner wall of thecavity such that the distal end of the lower blade 108 extends out ofthe cavity 28 and beyond the body 11. The distal end of the lower blade108 may be pointed, barbed or otherwise sharp in order to be received inan upper (superior) spine disc and/or vertebra.

FIGS. 2 and 3 show an instrument or tool 100 for installing/implantingthe TLIF implant 10. The instrument 100 includes a handle 101 of agenerally cylindrical shape (however, other shapes may be used) with arear end 102 and a front end 103. The rear end 102 is generallydisk-shaped in like manner as the handle 101 and includes knurling onits outer surface, but other shapes may be used. The front end 103 islikewise generally disk-shaped in like manner as the handle 101, butother shapes may be used. A yoke 104 extends from the front end 103 ofthe handle 101 and supports a hollow shaft or cannula 105. A tip 106 isprovided at the distal end of the hollow shaft 105 and provides an exitopening of the hollow shaft 105. The tip 106 has a first elongated prong107 and a second elongated prong (not seen) opposite the first elongatedprong 107, the nomenclature first and second being arbitrary. The firstelongated prong 107 is configured for reception in the first elongatedgroove 22 of the TLIF implant 10, while the second elongated prong (notseen) is configured for reception in the second elongated groove 30 ofthe TLIF implant 10 in like manner to the first.

The tool 100 allows the use of a rod 112 for contacting and pushing theupper and lower blades 109, 108 out of the cavity 38 of the TLIF implant10 after insertion. The tool 100 also allows the use of the rod 112 orother rod for inserting bone graft/bone graft material into the cavity38 of the TLIF implant 10 after the TLIF implant 10 has been implantedand the impacted first and second blades 29 are extended. In order toaccommodate the rod 112, the first and second ends 102, 103 of thehandle 101 both have a central hole. The rod 112 extends through thehandle 101 and the holes of the first and second ends 102, 103. The rod112 also extends through the yoke and the hollow shaft 105. The lengthof the rod 112 is sufficient to extend beyond the tip 106 of the hollowshaft 105 and reach into the TLIF implant 10 when the TLIF implant 10 isheld by the instrument 100, particularly the first and second elongatedprongs 107, not seen, during installation of the TLIF implant 10. A knob113 is provided at the proximal end of the rod 112 for controllingmovement of the rod 112. The rod 112 may be removed from the shaft 105and handle 101 and another rod 112 inserted in its place.

As seen in FIG. 3, the hollow shaft 105 includes one or more windows oropenings, three windows 110 a, 110 b, and 110 c of which are shown as anexample. The hollow shaft 105 may have more or less than three windowsas desired. The windows 110 a, 110 b, and 110 c are generally oval inshape and are preferably, but not necessarily, all situated in the sameside of the hollow shaft 105. Other shapes and positions may be used.While not necessary, the window 110 a is larger than the windows 110 b,110 c to allow for graft insertion and pushing into the cavity 28 of theTLIF implant 10 via the unthreaded hole 23 of the body 11. The end ofone the graft insertion/pushing rods may be funnel shaped to drive thegraft along the hollow shaft 105 and into the cavity 38 of the implantbody 11 via the implant hole 23.

Per the method of installation, the upper and lower blades 109, 108 ofthe TLIF implant 10 are held or impacted within the cavity 38 of thebody 11 of the TLIF implant 10 before the implant is installed (e.g.FIG. 1). While the first and second elongated prongs 107, (not seen)hold the TLIF implant 10 through reception of the first elongated prong107 into the first elongated lateral side slot 22 of the TLIF body 11,and the second elongated prong (not seen) in the second elongatedlateral side slot 30 of the TLIF body 11, the rod 112 is manipulated viathe knob 113 to push the distal end of the rod (not seen) through thehole 23 and into the cavity 38 of the body 11. The distal tip (not seen)of the rod 112 is configured to push the upper blade 109 along the upperledges 29, (not seen) of the first and second interior lateral walls 31,(not seen) of the cavity 38, and the lower blade 108 along the lowerledges (not seen) of the first and second interior lateral walls 31,(not seen) of the cavity 38. The upper blade 109 is guided along theupper ledges to project or extend the end of the upper blade 109 out ofthe cavity 38, as seen in FIG. 2. The lower blade 108 is guided alongthe lower ledges to project or extend the end of the lower blade 108 ofthe cavity 38, as seen in FIG. 2. The upper and lower blades 109, 108remain extended after installation of the TLIF implant 10 to help holdthe implant in place.

A method of installation includes placing an impacted blade TLIF implant10 onto the installation instrument or tool 100. Particularly, the firstand second prongs at the tip of the shaft of the installation tool arereceived in the first and second outside lateral slots of the impactedblade TLIF implant body. The installation tool is ready to place theimplant into the vertebral space previously occupied by a vertebra, thevertebra having been surgically removed prior to implant installation.Once the impacted blade TLIF implant has been placed at the desiredlocation, a rod 112 with a tip configured to push the impacted blades upand out of the implant cavity is used in the installation tool and ismoved to expel the blades. The blade pushing rod is removed and a graftpushing rod is received in the installation tool. Graft is insertedthrough the windows of the tool shaft. The graft pushing rod is moved topush the graft through the shaft and into the cavity of the installedTLIF implant through the end hole. Once a sufficient amount of graft hasbeen pushed into the implant cavity, the rod and installation tool areremoved.

It should be appreciated that dimensions of the components, structures,and/or features of the present TLIF implant and installation instrumentmay be altered as desired within the scope of the present disclosure.

What is claimed is:
 1. A kit for installing a spine implant for atransforaminal lumbar interbody fusion (TLIF), the kit comprising: aninstallation tool; and a TLIF implant; the TLIF implant comprising: abody made of a biocompatible material and defining a superior surface,an inferior surface, a curved first end of the body, a planar second endof the body, a first lateral side between the first end and the secondend, and a second lateral side between the first end and the second end,the body having: a cavity extending through the body from the superiorsurface to the inferior surface, the cavity defining a first lateralinterior wall, and a second lateral interior wall; a first channelextending from the planar second end a first length along the firstlateral side; a second channel extending from the planar second end asecond length along the second lateral side; a bore in the planar secondend, the bore in communication with the cavity; a first superior guidein the first lateral interior wall; a second superior guide in thesecond lateral interior wall, the first superior guide and the secondsuperior guide defining a superior blade guide; a first inferior guidein the first lateral interior wall; and a second inferior guide in thesecond lateral inferior wall, the first inferior guide and the secondinferior guide defining an inferior blade guide; a first blade situatedin the cavity on the superior blade guide, the first blade held in thecavity during implantation of the body but movable along the superiorblade guide after implantation of the body such that a distal end of thefirst blade extends out of the cavity from the superior surface andbeyond the body; and a second blade situated in the cavity on theinferior blade guide, the second blade held in the cavity duringimplantation of the body but movable along the inferior blade guideafter implantation of the body such that a distal end of the secondblade extends out of the cavity from the inferior surface and beyond thebody; the installation tool comprising: a handle; a hollow shaftconnected to the handle and having a tip with a first prong configuredto be received in the first channel of the body of the TLIF implant, anda second prong configured to be received in the second channel of thebody of the TLIF implant, the tip holding the TLIF implant duringinstallation thereof; a pusher rod configured to extend through thehollow shaft and extend the first and second blades; and a graft rodconfigured to extend through the hollow shaft and introduce graftmaterial into the TLIF implant.
 2. The kit of claim 1, furthercomprising: first serrations on the superior surface of the body of theTLIF implant; and second serrations on the inferior surface of the bodyof the TLIF implant.
 3. The kit of claim 2, further comprising: a borein the body of the TLIF implant proximate the first end, the boreconfigured to receive a radiolucent marker.
 4. The kit of claim 2,wherein: the distal end of the first blade of the TLIF implant has afirst barb; and the distal end of the second blade of the TLIF implanthas a second barb.
 5. The kit of claim 2, wherein: the first lateralchannel of the TLIF implant extends from the bore in the planar secondend along the first length of the first lateral side of the body; andthe second lateral channel of the TLIF implant extends from the bore inthe planar second end along the second length of the second lateral sideof the body.
 6. The kit of claim 5, wherein: the first length extends toproximate the first end of the body of the TLIF implant; and the secondlength extends to proximate the first end of the body of the TLIFimplant.
 7. The kit of claim 1, wherein the hollow shaft of theinstallation tool has an opening configured to allow graft material tobe inserted into the hollow shaft of the installation tool.
 8. The kitof claim 1, wherein the hollow shaft of the installation tool has aplurality of openings configured to allow graft material to be insertedinto the hollow shaft of the installation tool.